"I even learned a few things about PGP from Simson's informative book." --Phil Zimmermann, Author of PGP

"Pretty Good Privacy is written with passion, brevity and sophistication, providing a good read on a very important subject." --Canadian Computer Reseller

"Since the release of PGP 2.0 from Europe in the fall of 1992, PGP's popularity and usage has grown to make it the de-facto standard for email encyrption. Simson's book is an excellent overview of PGP and the history of cryptography in general. It should prove a useful addition to the resource library for any computer user, from the UNIX wizard to the PC novice." --Derek Atkins, PGP Development Team, MIT

"For a highly readable account of cryptography in general and public key encryption in particular, you won't do better than Simson Garfinkel's
PGP from O'Reilly and Associates." --Alexander Wolfe, Electronic Engineering Times

"Simson Garfinkel tells well one of the most fascinating stories in the history of computing...a clear and engaging introduction to the most revolutionary computer programs ever written." --Marc Rotenberg, Director, Electronic Privacy Information Center

"A great introduction to cryptology and PGP. Useful for anyone interested in using modern crypto tools for ensuring liberty in our modern age. Every cypherpunk needs a copy!" --Tim May, Co-founder of Cypherpunks

"This book contains an excellent, accurate history of public key cryptography, from its invention to the present." --Jim Bidzos, President, RSA Data Security, Inc.

"I thought I knew everything about PGP, but I didn't! There are some things in here I'd never heard of. Authoritative." --Eric Hughes, Cypherpunks co-founder

"Finally, an authoritative book about a very popular and somewhat controversial subject has been released...Simson Garfinkel has done an extremely thorough job of showing us all the technical ins-and-outs of PRETTY GOOD PRIVACY...This book is not only for those wanting to learn how to master PGP (although it certainly will show you how), but for anyone interested in cruptography and concerned with our fundamental right ot privacy...In my opinion this is the most fascinating computer story I've read since Cliff Stoll's classic yarn several years ago." --Michael Crestohl, Eco Software, Net posting

"This book teaches you everything you need to know about PGP, and provides a wealth of interesting information about computer cryptography in general." --Harley Hahn and Wendy Murdock, Boardwatch, March 1995

"Finally, an authoritative book about a very popular and somewhat controversial subject has been released. It's not only about Phil Zimmermann's encryption program, PRETTY GOOD PRIVACY, (PGP for short) although it covers the latest version (2.6.2) in great detail. Rather it is also a discussion of the concept of the people's right to privacy in a free society and governmental attempts to abridge these rights. PGP is freely available encryption/ decryption software that provides individuals with an extremely powerful cryptography package that has, in the past, been available only to the military, intelligence agencies and very large corporations.

"PGP is used to encrypt and decrypt files and e-mail. You can also 'sign' documents with a tamper-proof digital signature to assure authenticity and origin. PGP is based upon the RSA algorithm, developed at MIT by mathematicians Rivest, Adleman and Shamir and the Diffie-Hellman concept of multi-user techniques commonly known as 'Public Key' cryptography. From the beginning there were conflicts over patent infringements and U.S. State Department export restrictions that consider cryptographic materials to be munitions! Phil Zimmermann has taken on the establishment and his many legal battles continue even now. A special defense fund has been set up for supporters to help him with his legal expenses as he continues to stand up to the government on this all-important issue and challenge to our right to privacy.

"Simson Garfinkel has done an extremely thorough job of showing us all the technical ins-and-outs of PRETTY GOOD PRIVACY and how to install it and use it on a PC, Macintosh or UNIX platform. He even tells us where to get the latest version (for free!) by FTP from the server at M.I.T. provided you have full Internet access! Moreover, he has gone much deeper into the PGP/privacy saga by detailing the 'behind-the-scenes' stories of how Phil Zimmermann developed PGP, chronicling the patent infringement and export restriction conflicts and taking a human-interest look at the people involved in these all important legal precedent-setting actions that are still not resolved in the courts and probably won't be for a long time to come.

"I have been following the PGP story since Version 1.0 was released in late 1991. Many others share my interest - in fact there are several USENET newsgroups (including alt.security.pgp) and a mailing list totally devoted to discussion of PGP matters and right-to-privacy issues. When O'Reilly informed me a PGP book was forthcoming I was most anxious to review it. The fine folks at O'Reilly have done a truly superb job with the graphics and illustrations.

"This book is not only for those wanting to learn how to master PGP (although it certainly will show you how), but for anyone interested in cryptography and concerned with our fundamental right to privacy. Simson Garfinkel's book didn't disappoint me - it accurately tells the whole PGP story and Garfinkel promises that future editions will continue to do so. In my opinion this is the most fascinating computer story I've read since Cliff Stoll's classic yarn several years ago. It won't disappoint you either."

--(C) 1995 H. Michael Crestohl, Nahant, Massachusetts

"PGP: Pretty Good Privacy is also the title of Simson Garfinkel's latest book, published by O'Reilly...the folks who brought you
The Whole Internet User's Guide & Catalog. Garfinkel's beautifully written book provides three things: a potted history of cryptography and computers; the story of Phil Zimmermann and his development of PGP; and then a how-to guide for using PGP on any Mac, IBM or Unix computer. The most exciting part of the book is Garfinkel's description of the US National Security Agency's attempts to thwart every effort by academics and corporations to develop good encryption -- as they would make it hard for the agency to read their mail. It also serves as the first printed guide to this handy program, which is now in use wherever the Internet reaches."

--New Scientist, October 1994

"For those of you who follow the cryptography world, one of the more interesting recent developments has been the PGP (Pretty Good Privacy) encryption program. Developed by an individual, it is a relatively strong encryption technique that runs on a variety of platforms, is available as both shareware and commercially, and can be downloaded from computer sites around the world. If you don't use PGP, you might have noticed strange ASCII signatures in postings to USENET - often these are personal signatures for people who use PGP.

"An excellent guide both to the use of PGP and its' and cryptography's history...is...PGP:Pretty Good Privacy...written by Simson Garfinkel...available from O'Reilly & Associates.... I am not sure of the price, but O'Reilly's books are reasonably priced. "Amongst other things, the book has a fair amount of material on the patent aspects of cryptography...including the latest ranglings involving RSA. [It]...is...excellent...both as a user guide to PGP and as a history of cryptography. For PGP, it explains how the program works, how to get a copy of the program and install it, and how to use the various options. I don't use PGP because encryption key management to me sounded as burdensome as contact lens cleaning management, which I also don't use. However Simson's explanation of PGP is convincing enough for me to eventually use PGP, once I find something worth encrypting. "The historical treatment of cryptography and PGP was quite interesting, with many ancedotal stories about the various characters involved. As the book goes to press, patent and business shenigans continue, so the book is quite timely. The book also explores some of the privacy, policy and national security aspects of cryptography, including the recent brouhaha over the Clipper chip, triple-DES, and the whys of dual secret key PGP. (Fortunately for those weak at heart, Galois Fields are not mentioned). "So if you are in to this stuff, or considering using PGP, get a copy of the book."

--Greg Aharonian, Publisher of Internet Patent News Service and Consultant for Software Patenting and Prior Art

"There have been lots of books about cryptography but if you are a practical computer user then it is hard to understand what it all means. Garfinkel's book hits the right level. It gives a comprehensible introduction to the general principles of cryptography. It does that in the context of the best current practical program for ordinary computer users. This is a good book for computer-oriented people who just want to understand the significance of cryptography as well as people considering using the PGP program itself.

"The most entertaining part of the book describes the conflicts between people, business organizations, government organizations and professional societies in the area of cryptography. This is an amazing saga that deserves a book to itself, not to mention a TV series. Garfinkel's summary of the drama is a well written fast-paced report of the facts and of the opinions of the combatants. I'd recommend this to anyone trying to understand the place of cryptography in the "Information Society" of the future.

"The decription of how to use PGP itself is clear and straightforward. This is a rapidly evolving area and I'm sure O'Reilly will need to publish regular updated versions of this book. I hope the future versions will provide more information about the many support programs that have grown up around PGP to make it easier to use. I know that some are of dubious quality, and perhaps they all are but it would be interesting to know more about them and what they are trying to do. It would also be useful to hear more about applications of PGP such as Netmarket's Internet shop using PGP extensions to the WWW.

"A slight warning to the reader. The book uses without comment the convention that the non-public half of a public key pair is called the 'secret' key. The shared key in conventional symmetric key cryptography is called the "private" key. Other people in the literature reverse this use of 'secret' and 'private'."